Electric bell buzzer



ELECTRIC BELL BUZ ZER Filed Nov. 1, 1940 20/ a gwwm: "16' 16 IsaacGooclbzr Patented Feb. 29, 1944 OFFICE ELECTRIC BELL BUZZER IsaacGoodbar, Buenos Aires, Argentina Application November 1, In ArgentinaSep 3 Claims.

The present invention consists in and has for its object a novelelectric bell, buzzer or the like device, which will operate directlywith alternating current from power mains but produce a harmless voltageat the call buttons.

By the use of the present invention, a considerable economy is achieved,since the transformer is eliminated. a

The invention, in its embodiment as a buzzer, offers the furtheradvantage that the usual sparking at the make and break points whichgenerally causes premature wearing away of the contacts, does not occur.

The present invention furthermore envisages other objects which will'bemade apparent in the course of the following description.

In order that the invention may be clearly understood and readilycarried into practice, a

preferred embodiment thereof has been shown by way of example in theaccompanying drawing, in which a combined bell and buzzer in accordancewith the present invention is illustrated in diagrammatic form and inwhich;

Figure 1 is a diagrammatic view of the combined bell and buzzer with awiring diagram,

Figure 2 is a sectional view taken through the armature, and

Figure 3 is a wiring diagram.

The drawing shows a bell which, in addition to the advantages alreadymentioned, possesses that of being able to operate either as abell or asa buzzer. Consequently it combines in itself three devices, namely, atransformer, a-bell and a buzzer.

Inthe embodiment shown, the novel electric sound signalling deviceaccording to the present invention, comprises an induction transformer20 consisting of a core 1 and two windin s 2,3, of which the primary 2is connected at one end by a conductor 4, and at the other end by asecond conductor 5 of the power mains.

The ends of the secondary winding 3, on the other hand, are connected byleads 6 and I respectively to terminals 8 and 9, which form part to thesupply terminals 22, 22"

1940, Serial No. 363,9 tember 24, 1940 windings 2, 3, across one face ofhas coupled to it of a local buzzer call circuit hereinafter described.

A conductor I 8 branches from lead 1 at a point intermediate terminal 9and the corresponding end of the secondary 3. Said conductor I 8terminates at a support '24 in which is adiustably held a screw l1whichis in contact with a re-. silient tongue l3 fast on armature I I).Said tongue is at its end remote from the screw ll secured to a supportH, which is connected by a I0 is disposed to extend between the coils ofthe the core I, and a bell hammer ll adapted to strike a bell body l2suitably mounted on a stem 40 when the armature vibrates. The hammer maybe attached directly to the armature or to the resilient tongue l3. Theterminal l6 forms part of a local bell call circuit including terminal8.

The-ca11 buttons 26 vice to function as a adapted to cause the debuzzer,are connected between the terminals 8 and 9 as shown, whereas thebuttons 34, designed to cause the device to function as a bell, areconnected between terminals I6 and 8 by conductors 28, 36 and 38 asshown.

When none of the buttons is depressed, the transformer runs on no load.The primary winding 2 is traversed bya weak current which generates alow intensity alternating magnetic field. The major portion of this fluxflows through the core I, and passes through the window of the coil ofwinding 3, since this circuit has a very low reluctance. On the otherhand, a negligible portion of the said magnetic flux passes through thearmature l0 and the associated airaps, thus following a path which isobviously of high reluctance. mature is so small, the armature willremain at rest, since it is only weakly magnetized. I

If one of the buttons .14 connected between terminals I6 and 8 isdepressed, the secondary circuit of the transformer is establishedthrough conductors I and I8, support 24, screw l1, resilient tongue l3,support I, conductor l5, terminal [6, conductor 38, the selected callbutton 34 of the local bell call circuit, conductors 36 and 28, terminal8. and conductor 6. In these circumstances there will pass through thesecondary winding 3 an alternating current which, at every instant, willhave a sense such that, according to Lenzs law, a flux will be generatedwhich is at all times opposed to that produced by the primary winding,that is to say, said flux will find considerable resistance to itspassage through the window of the con of winding-3.

This is equivalent to saying that the reluctance of the core increasesconsiderably, reaching a higher value than that Of the armature with itsair-gaps. Moreover the primary magnetic flux also is greatly increasedowing to the increase in the reluctance which causes a reduction in theself-induction of the winding 2, and a consequent increase in theintensity of the current passing conductor l5 to a terminal "5. Thearmature through the primary.

As the flux passing through the are .For these reasons an intensemagnetic flux v flows through armature It, thus subjecting said armatureto a powerful alternating magnetization. I

Consequently, armature II is attracted to core I, whereby the secondarycircuit is broken at the screw 51' and the resilient tongue it, thuscaushammer II will strike the bell body I! and the device will operateas a bell.

If, on the other hand, one of the buttons 26 connected in the localbuzzer call circuit, between terminals 8 and 9, be depressed, thesecondary circuit will remain closed solong as the button is in the callposition, the winding 3 being shortcircuited by conductor 6, terminal 8,conductors 28 and 30, the selected callbuttonit, conductor 32, terminal9 and conductor I, and the vibration amplitude of the armature will bedetermined by the now higher frequency of the current, and will beinsuillcient to cause the hammer to strike the gong Ill. The device willconsequently operate as a buzzer.

It is obvious that, if it is desired to construct a device which willfunction exclusively as a buzzer, terminal 16, conductor [5, bell bodyit, screw l'l, support 24, conductor l8, hammer Ii, the bell callbuttons 34 and their associated conductors 38 and 36, will have to beeliminated.

core, limb of said core opposite the'primary windin a bell call circuitand a buzzer call circuit both "cuit and an interruptorawhich is inseries with the secondary winding and the buttons to cause the bellcircuit to operate at a frequency substantially lower than thetransformer supply frequency, and a vibratory bell striking memberattached to said armature'to cause. the buzzer call Under theseconditions, the device will be very cheap and at no point therein willsparking occur by reason of the breaking of a circuit.

It is also possible to construct an apparatus in I accordance with thepresent invention, which will operate only as a bell and without anysparking. As a relay mechanism the device is applicable in all cases inwhich alternating power current is available and it is desired that thevoltage at the control point shall be low.

The operationof the device when usedas just I indicated will be readilyunderstood and requires not further explanation for those skilled in thear Obviously a number of constructional and detail modifications may bemade in the device,

without departing from the nature and scopeof the present invention asdefined in the appended claims.

. Having now particularly ascertained and de-' scribed the nature of thepresent invention and the manner in which the,same is to be performed,whatIclaim is:

1. Electric bell and buzzer signal system comprising a rectangularmagnetic core, a transformer primary winding on one limb of said circuitto operate at the same supply frequency.

2. A combined electric bell and buzzer device adapted to beconnected toalternating current power mains, comprising an induction transformerhaving a core, nected to said power mains and a single secondary windingconnected to a bell call circuit including bell call buttons, and to abuzzer call circuit including buzzer call buttons, a single vibratoryarmature with a natural frequency of vibration substantially lower thanthat of the current supply to the transformer, said armature beingmounted to be attracted to said core upon energization of both of saidwindings and in magnetic shunt with atleast one of said windings, a bellhammer secured to one end of said armature to move therewith, a bellbody mounted to be struck by said hammer upon vibration of saidarmature, a resilient tongue member sup-I porting the armature, asupport extendin over said armature and supporting an electrically coneductive screw making and breaking contact with said tongue member, and asecond support hav ing secured thereto the end of the tongue mem berremote from the .hammer and being electrically connected to the bellcall circuit together tween the windings, a resilient tonguemembersecured at one end and to which the armature 4 is secured, asupport cooperating with the tongue member, abell hammer secured to andmovable with the armature, a buzzer call circuit connected to thesecondary winding and having a closure member which when operatedvibrates the tong e member and the armature slightly tofunction as abuzzer, and a hell can circuit connected to the secondary winding, a'tongue member and the support and having a closure member which whenoperated vibrates the tongue member and the armature and with the latterthe bell hammer at such vibrations to function as a bell.

. ISAAC GOODBAR.

a transformer secondary winding on the a primary winding con-

